According to miniaturization of a semiconductor device having an active region of a MOS transistor, the size of the active region of the MOS transistor has been gradually reduced. Thereby, the channel length of the MOS transistor also has been reduced. If the channel length of the MOS transistor becomes smaller, a short channel effect (SCE) may occur and the operating performance of the MOS transistor may suffer.
Therefore, various studies have been conducted to increase the operating performance of the MOS transistor even though the size of the active region of the MOS transistor has been reduced. One of them is to use a fin field effect transistor (FinFET) having a fin-type active region. Generally, the fin-type active region may be formed on a substrate of the semiconductor device by partially etching the substrate using an etch process. As a result, the substrate may be damaged by the etch process and the surface roughness of the substrate may increase. If the surface roughness is not cured, the operating performance of the MOS transistor suffer.